/*
 *  SSL client with certificate authentication
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf     printf
#define mbedtls_fprintf    fprintf
#define mbedtls_snprintf   snprintf
#endif

#if !defined(MBEDTLS_ENTROPY_C) ||				      \
	!defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
	!defined(MBEDTLS_NET_C) || !defined(MBEDTLS_CTR_DRBG_C)
int main(void)
{
	mbedtls_printf("MBEDTLS_ENTROPY_C and/or "
		       "MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_CLI_C and/or "
		       "MBEDTLS_NET_C and/or MBEDTLS_CTR_DRBG_C and/or not defined.\n");
	return(0);
}
#else

#include "mbedtls/net.h"
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/certs.h"
#include "mbedtls/x509.h"
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "mbedtls/timing.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define DFL_SERVER_NAME         "server"
#define DFL_SERVER_ADDR         "192.168.43.4"
#define DFL_SERVER_PORT         "4433"
#define DFL_REQUEST_PAGE        "/"
#define DFL_REQUEST_SIZE        -1
#define DFL_DEBUG_LEVEL         0
#define DFL_NBIO                0
#define DFL_READ_TIMEOUT        0
#define DFL_MAX_RESEND          0
#define DFL_CA_FILE             ""
#define DFL_CA_PATH             ""
#define DFL_CRT_FILE            ""
#define DFL_KEY_FILE            ""
#define DFL_PSK                 ""
#define DFL_PSK_IDENTITY        "Client_identity"
#define DFL_ECJPAKE_PW          NULL
#define DFL_FORCE_CIPHER        0
#define DFL_RENEGOTIATION       MBEDTLS_SSL_RENEGOTIATION_DISABLED
#define DFL_ALLOW_LEGACY        -2
#define DFL_RENEGOTIATE         0
#define DFL_EXCHANGES           1
#define DFL_MIN_VERSION         -1
#define DFL_MAX_VERSION         -1
#define DFL_ARC4                -1
#define DFL_AUTH_MODE           -1
#define DFL_MFL_CODE            MBEDTLS_SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC          -1
#define DFL_RECSPLIT            -1
#define DFL_DHMLEN              -1
#define DFL_RECONNECT           0
#define DFL_RECO_DELAY          0
#define DFL_RECONNECT_HARD      0
#define DFL_TICKETS             MBEDTLS_SSL_SESSION_TICKETS_ENABLED
#define DFL_ALPN_STRING         NULL
#define DFL_TRANSPORT           MBEDTLS_SSL_TRANSPORT_STREAM
#define DFL_HS_TO_MIN           0
#define DFL_HS_TO_MAX           0
#define DFL_FALLBACK            -1
#define DFL_EXTENDED_MS         -1
#define DFL_ETM                 -1

#define GET_REQUEST "GET %s HTTP/1.0\r\nExtra-header: "
#define GET_REQUEST_END "\r\n\r\n"

#if defined(MBEDTLS_X509_CRT_PARSE_C)
#if defined(MBEDTLS_FS_IO)
#define USAGE_IO											  \
	"    ca_file=%%s          The single file containing the top-level CA(s) you fully trust\n"	  \
	"                        default: \"\" (pre-loaded)\n"						  \
	"    ca_path=%%s          The path containing the top-level CA(s) you fully trust\n"		  \
	"                        default: \"\" (pre-loaded) (overrides ca_file)\n"			  \
	"    crt_file=%%s         Your own cert and chain (in bottom to top order, top may be omitted)\n" \
	"                        default: \"\" (pre-loaded)\n"						  \
	"    key_file=%%s         default: \"\" (pre-loaded)\n"
#else
#define USAGE_IO \
	"    No file operations available (MBEDTLS_FS_IO not defined)\n"
#endif /* MBEDTLS_FS_IO */
#else
#define USAGE_IO ""
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
#define USAGE_PSK							\
	"    psk=%%s              default: \"\" (in hex, without 0x)\n"	\
	"    psk_identity=%%s     default: \"Client_identity\"\n"
#else
#define USAGE_PSK ""
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
#define USAGE_TICKETS \
	"    tickets=%%d          default: 1 (enabled)\n"
#else
#define USAGE_TICKETS ""
#endif /* MBEDTLS_SSL_SESSION_TICKETS */

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
#define USAGE_TRUNC_HMAC \
	"    trunc_hmac=%%d       default: library default\n"
#else
#define USAGE_TRUNC_HMAC ""
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
#define USAGE_MAX_FRAG_LEN					  \
	"    max_frag_len=%%d     default: 16384 (tls default)\n" \
	"                        options: 512, 1024, 2048, 4096\n"
#else
#define USAGE_MAX_FRAG_LEN ""
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
#define USAGE_RECSPLIT \
	"    recsplit=0/1        default: (library default: on)\n"
#else
#define USAGE_RECSPLIT
#endif

#if defined(MBEDTLS_DHM_C)
#define USAGE_DHMLEN \
	"    dhmlen=%%d           default: (library default: 1024 bits)\n"
#else
#define USAGE_DHMLEN
#endif

#if defined(MBEDTLS_SSL_ALPN)
#define USAGE_ALPN					      \
	"    alpn=%%s             default: \"\" (disabled)\n" \
	"                        example: spdy/1,http/1.1\n"
#else
#define USAGE_ALPN ""
#endif /* MBEDTLS_SSL_ALPN */

#if defined(MBEDTLS_SSL_PROTO_DTLS)
#define USAGE_DTLS							     \
	"    dtls=%%d             default: 0 (TLS)\n"			     \
	"    hs_timeout=%%d-%%d    default: (library default: 1000-60000)\n" \
	"                        range of DTLS handshake timeouts in millisecs\n"
#else
#define USAGE_DTLS ""
#endif

#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
#define USAGE_FALLBACK \
	"    fallback=0/1        default: (library default: off)\n"
#else
#define USAGE_FALLBACK ""
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
#define USAGE_EMS \
	"    extended_ms=0/1     default: (library default: on)\n"
#else
#define USAGE_EMS ""
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
#define USAGE_ETM \
	"    etm=0/1             default: (library default: on)\n"
#else
#define USAGE_ETM ""
#endif

#if defined(MBEDTLS_SSL_RENEGOTIATION)
#define USAGE_RENEGO					   \
	"    renegotiation=%%d    default: 0 (disabled)\n" \
	"    renegotiate=%%d      default: 0 (disabled)\n"
#else
#define USAGE_RENEGO ""
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
#define USAGE_ECJPAKE \
	"    ecjpake_pw=%%s       default: none (disabled)\n"
#else
#define USAGE_ECJPAKE ""
#endif

#define USAGE										\
	"\n usage: ssl_client2 param=<>...\n"						\
	"\n acceptable parameters:\n"							\
	"    server_name=%%s      default: localhost\n"					\
	"    server_addr=%%s      default: given by name\n"				\
	"    server_port=%%d      default: 4433\n"					\
	"    request_page=%%s     default: \".\"\n"					\
	"    request_size=%%d     default: about 34 (basic request)\n"			\
	"                        (minimum: 0, max: 16384)\n"				\
	"    debug_level=%%d      default: 0 (disabled)\n"				\
	"    nbio=%%d             default: 0 (blocking I/O)\n"				\
	"                        options: 1 (non-blocking), 2 (added delays)\n"		\
	"    read_timeout=%%d     default: 0 ms (no timeout)\n"				\
	"    max_resend=%%d       default: 0 (no resend on timeout)\n"			\
	"\n"										\
	USAGE_DTLS									\
	"\n"										\
	"    auth_mode=%%s        default: (library default: none)\n"			\
	"                        options: none, optional, required\n"			\
	USAGE_IO									\
	"\n"										\
	USAGE_PSK									\
	USAGE_ECJPAKE									\
	"\n"										\
	"    allow_legacy=%%d     default: (library default: no)\n"			\
	USAGE_RENEGO									\
	"    exchanges=%%d        default: 1\n"						\
	"    reconnect=%%d        default: 0 (disabled)\n"				\
	"    reco_delay=%%d       default: 0 seconds\n"					\
	"    reconnect_hard=%%d   default: 0 (disabled)\n"				\
	USAGE_TICKETS									\
	USAGE_MAX_FRAG_LEN								\
	USAGE_TRUNC_HMAC								\
	USAGE_ALPN									\
	USAGE_FALLBACK									\
	USAGE_EMS									\
	USAGE_ETM									\
	USAGE_RECSPLIT									\
	USAGE_DHMLEN									\
	"\n"										\
	"    arc4=%%d             default: (library default: 0)\n"			\
	"    min_version=%%s      default: (library default: tls1)\n"			\
	"    max_version=%%s      default: (library default: tls1_2)\n"			\
	"    force_version=%%s    default: \"\" (none)\n"				\
	"                        options: ssl3, tls1, tls1_1, tls1_2, dtls1, dtls1_2\n"	\
	"\n"										\
	"    force_ciphersuite=<name>    default: all enabled\n"			\
	" acceptable ciphersuite names:\n"

/*
 * global options
 */
struct options {
	const char *server_name;        /* hostname of the server (client only)     */
	const char *server_addr;        /* address of the server (client only)      */
	const char *server_port;        /* port on which the ssl service runs       */
	int debug_level;                /* level of debugging                       */
	int nbio;                       /* should I/O be blocking?                  */
	uint32_t read_timeout;          /* timeout on mbedtls_ssl_read() in milliseconds    */
	int max_resend;                 /* DTLS times to resend on read timeout     */
	const char *request_page;       /* page on server to request                */
	int request_size;               /* pad request with header to requested size */
	const char *ca_file;            /* the file with the CA certificate(s)      */
	const char *ca_path;            /* the path with the CA certificate(s) reside */
	const char *crt_file;           /* the file with the client certificate     */
	const char *key_file;           /* the file with the client key             */
	const char *psk;                /* the pre-shared key                       */
	const char *psk_identity;       /* the pre-shared key identity              */
	const char *ecjpake_pw;         /* the EC J-PAKE password                   */
	int force_ciphersuite[2];       /* protocol/ciphersuite to use, or all      */
	int renegotiation;              /* enable / disable renegotiation           */
	int allow_legacy;               /* allow legacy renegotiation               */
	int renegotiate;                /* attempt renegotiation?                   */
	int renego_delay;               /* delay before enforcing renegotiation     */
	int exchanges;                  /* number of data exchanges                 */
	int min_version;                /* minimum protocol version accepted        */
	int max_version;                /* maximum protocol version accepted        */
	int arc4;                       /* flag for arc4 suites support             */
	int auth_mode;                  /* verify mode for connection               */
	unsigned char mfl_code;         /* code for maximum fragment length         */
	int trunc_hmac;                 /* negotiate truncated hmac or not          */
	int recsplit;                   /* enable record splitting?                 */
	int dhmlen;                     /* minimum DHM params len in bits           */
	int reconnect;                  /* attempt to resume session                */
	int reco_delay;                 /* delay in seconds before resuming session */
	int reconnect_hard;             /* unexpectedly reconnect from the same port */
	int tickets;                    /* enable / disable session tickets         */
	const char *alpn_string;        /* ALPN supported protocols                 */
	int transport;                  /* TLS or DTLS?                             */
	uint32_t hs_to_min;             /* Initial value of DTLS handshake timer    */
	uint32_t hs_to_max;             /* Max value of DTLS handshake timer        */
	int fallback;                   /* is this a fallback connection?           */
	int extended_ms;                /* negotiate extended master secret?        */
	int etm;                        /* negotiate encrypt then mac?              */
} opt;

static void my_debug(void *ctx, int level,
		     const char *file, int line,
		     const char *str)
{
	const char *p, *basename;

	/* Extract basename from file */
	for (p = basename = file; *p != '\0'; p++) {
		if (*p == '/' || *p == '\\') {
			basename = p + 1;
		}
	}

	mbedtls_fprintf((FILE *) ctx, "%s:%04d: |%d| %s", basename, line, level, str);
	fflush((FILE *) ctx);
}

/*
 * Test recv/send functions that make sure each try returns
 * WANT_READ/WANT_WRITE at least once before sucesseding
 */
static int my_recv(void *ctx, unsigned char *buf, size_t len)
{
	static int first_try = 1;
	int ret;

	if (first_try) {
		first_try = 0;
		return(MBEDTLS_ERR_SSL_WANT_READ);
	}

	ret = mbedtls_net_recv(ctx, buf, len);
	if (ret != MBEDTLS_ERR_SSL_WANT_READ) {
		first_try = 1; /* Next call will be a new operation */
	}
	return(ret);
}

static int my_send(void *ctx, const unsigned char *buf, size_t len)
{
	static int first_try = 1;
	int ret;

	if (first_try) {
		first_try = 0;
		return(MBEDTLS_ERR_SSL_WANT_WRITE);
	}

	ret = mbedtls_net_send(ctx, buf, len);
	if (ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
		first_try = 1; /* Next call will be a new operation */
	}
	return(ret);
}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
 * Enabled if debug_level > 1 in code below
 */
static int my_verify(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags)
{
	char buf[1024];

	((void) data);

	mbedtls_printf("\nVerify requested for (Depth %d):\n", depth);
	mbedtls_x509_crt_info(buf, sizeof(buf) - 1, "", crt);
	mbedtls_printf("%s", buf);

	if ((*flags) == 0) {
		mbedtls_printf("  This certificate has no flags\n");
	} else {
		mbedtls_x509_crt_verify_info(buf, sizeof(buf), "  ! ", *flags);
		mbedtls_printf("%s\n", buf);
	}

	return(0);
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

mbedtls_net_context server_fd;
unsigned char buf[MBEDTLS_SSL_MAX_CONTENT_LEN + 1];
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
unsigned char psk[MBEDTLS_PSK_MAX_LEN];
size_t psk_len = 0;
#endif
#if defined(MBEDTLS_SSL_ALPN)
const char *alpn_list[10];
#endif
const char *pers = "ssl_client2";
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_ssl_session saved_session;
#if defined(MBEDTLS_TIMING_C)
mbedtls_timing_delay_context timer;
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
uint32_t flags;
mbedtls_x509_crt cacert;
mbedtls_x509_crt clicert;
mbedtls_pk_context pkey;
#endif

int main(int argc, char *argv[])
{
	int ret = 0, len, tail_len, i, written, frags, retry_left;
	char *p, *q;
	const int *list;

	/*
	 * Make sure memory references are valid.
	 */
	mbedtls_net_init(&server_fd);
	mbedtls_ssl_init(&ssl);
	mbedtls_ssl_config_init(&conf);
	memset(&saved_session, 0, sizeof(mbedtls_ssl_session));
	mbedtls_ctr_drbg_init(&ctr_drbg);
#if defined(MBEDTLS_X509_CRT_PARSE_C)
	mbedtls_x509_crt_init(&cacert);
	mbedtls_x509_crt_init(&clicert);
	mbedtls_pk_init(&pkey);
#endif
#if defined(MBEDTLS_SSL_ALPN)
	memset((void * ) alpn_list, 0, sizeof(alpn_list));
#endif

	if (argc == 0) {
usage:
		if (ret == 0) {
			ret = 1;
		}

		mbedtls_printf(USAGE);

		list = mbedtls_ssl_list_ciphersuites();
		while (*list) {
			mbedtls_printf(" %-42s", mbedtls_ssl_get_ciphersuite_name(*list));
			list++;
			if (!*list) {
				break;
			}
			mbedtls_printf(" %s\n", mbedtls_ssl_get_ciphersuite_name(*list));
			list++;
		}
		mbedtls_printf("\n");
		goto exit;
	}

	opt.server_name = DFL_SERVER_NAME;
	opt.server_addr = DFL_SERVER_ADDR;
	opt.server_port = DFL_SERVER_PORT;
	opt.debug_level = DFL_DEBUG_LEVEL;
	opt.nbio = DFL_NBIO;
	opt.read_timeout = DFL_READ_TIMEOUT;
	opt.max_resend = DFL_MAX_RESEND;
	opt.request_page = DFL_REQUEST_PAGE;
	opt.request_size = DFL_REQUEST_SIZE;
	opt.ca_file = DFL_CA_FILE;
	opt.ca_path = DFL_CA_PATH;
	opt.crt_file = DFL_CRT_FILE;
	opt.key_file = DFL_KEY_FILE;
	opt.psk = DFL_PSK;
	opt.psk_identity = DFL_PSK_IDENTITY;
	opt.ecjpake_pw = DFL_ECJPAKE_PW;
	opt.force_ciphersuite[0] = DFL_FORCE_CIPHER;
	opt.renegotiation = DFL_RENEGOTIATION;
	opt.allow_legacy = DFL_ALLOW_LEGACY;
	opt.renegotiate = DFL_RENEGOTIATE;
	opt.exchanges = DFL_EXCHANGES;
	opt.min_version = DFL_MIN_VERSION;
	opt.max_version = DFL_MAX_VERSION;
	opt.arc4 = DFL_ARC4;
	opt.auth_mode = DFL_AUTH_MODE;
	opt.mfl_code = DFL_MFL_CODE;
	opt.trunc_hmac = DFL_TRUNC_HMAC;
	opt.recsplit = DFL_RECSPLIT;
	opt.dhmlen = DFL_DHMLEN;
	opt.reconnect = DFL_RECONNECT;
	opt.reco_delay = DFL_RECO_DELAY;
	opt.reconnect_hard = DFL_RECONNECT_HARD;
	opt.tickets = DFL_TICKETS;
	opt.alpn_string = DFL_ALPN_STRING;
	opt.transport = DFL_TRANSPORT;
	opt.hs_to_min = DFL_HS_TO_MIN;
	opt.hs_to_max = DFL_HS_TO_MAX;
	opt.fallback = DFL_FALLBACK;
	opt.extended_ms = DFL_EXTENDED_MS;
	opt.etm = DFL_ETM;

	for (i = 1; i < argc; i++) {
		p = argv[i];
		if ((q = strchr(p, '=')) == NULL) {
			goto usage;
		}
		*q++ = '\0';

		if (strcmp(p, "server_name") == 0) {
			opt.server_name = q;
		} else if (strcmp(p, "server_addr") == 0) {
			opt.server_addr = q;
		} else if (strcmp(p, "server_port") == 0) {
			opt.server_port = q;
		} else if (strcmp(p, "dtls") == 0) {
			int t = atoi(q);
			if (t == 0) {
				opt.transport = MBEDTLS_SSL_TRANSPORT_STREAM;
			} else if (t == 1) {
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			} else {
				goto usage;
			}
		} else if (strcmp(p, "debug_level") == 0) {
			opt.debug_level = atoi(q);
			if (opt.debug_level < 0 || opt.debug_level > 65535) {
				goto usage;
			}
		} else if (strcmp(p, "nbio") == 0) {
			opt.nbio = atoi(q);
			if (opt.nbio < 0 || opt.nbio > 2) {
				goto usage;
			}
		} else if (strcmp(p, "read_timeout") == 0) {
			opt.read_timeout = atoi(q);
		} else if (strcmp(p, "max_resend") == 0) {
			opt.max_resend = atoi(q);
			if (opt.max_resend < 0) {
				goto usage;
			}
		} else if (strcmp(p, "request_page") == 0) {
			opt.request_page = q;
		} else if (strcmp(p, "request_size") == 0) {
			opt.request_size = atoi(q);
			if (opt.request_size < 0 || opt.request_size > MBEDTLS_SSL_MAX_CONTENT_LEN) {
				goto usage;
			}
		} else if (strcmp(p, "ca_file") == 0) {
			opt.ca_file = q;
		} else if (strcmp(p, "ca_path") == 0) {
			opt.ca_path = q;
		} else if (strcmp(p, "crt_file") == 0) {
			opt.crt_file = q;
		} else if (strcmp(p, "key_file") == 0) {
			opt.key_file = q;
		} else if (strcmp(p, "psk") == 0) {
			opt.psk = q;
		} else if (strcmp(p, "psk_identity") == 0) {
			opt.psk_identity = q;
		} else if (strcmp(p, "ecjpake_pw") == 0) {
			opt.ecjpake_pw = q;
		} else if (strcmp(p, "force_ciphersuite") == 0) {
			opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id(q);

			if (opt.force_ciphersuite[0] == 0) {
				ret = 2;
				goto usage;
			}
			opt.force_ciphersuite[1] = 0;
		} else if (strcmp(p, "renegotiation") == 0) {
			opt.renegotiation = (atoi(q)) ? MBEDTLS_SSL_RENEGOTIATION_ENABLED :
					    MBEDTLS_SSL_RENEGOTIATION_DISABLED;
		} else if (strcmp(p, "allow_legacy") == 0) {
			switch (atoi(q)) {
			case -1: opt.allow_legacy = MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE; break;
			case 0:  opt.allow_legacy = MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION; break;
			case 1:  opt.allow_legacy = MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION; break;
			default: goto usage;
			}
		} else if (strcmp(p, "renegotiate") == 0) {
			opt.renegotiate = atoi(q);
			if (opt.renegotiate < 0 || opt.renegotiate > 1) {
				goto usage;
			}
		} else if (strcmp(p, "exchanges") == 0) {
			opt.exchanges = atoi(q);
			if (opt.exchanges < 1) {
				goto usage;
			}
		} else if (strcmp(p, "reconnect") == 0) {
			opt.reconnect = atoi(q);
			if (opt.reconnect < 0 || opt.reconnect > 2) {
				goto usage;
			}
		} else if (strcmp(p, "reco_delay") == 0) {
			opt.reco_delay = atoi(q);
			if (opt.reco_delay < 0) {
				goto usage;
			}
		} else if (strcmp(p, "reconnect_hard") == 0) {
			opt.reconnect_hard = atoi(q);
			if (opt.reconnect_hard < 0 || opt.reconnect_hard > 1) {
				goto usage;
			}
		} else if (strcmp(p, "tickets") == 0) {
			opt.tickets = atoi(q);
			if (opt.tickets < 0 || opt.tickets > 2) {
				goto usage;
			}
		} else if (strcmp(p, "alpn") == 0) {
			opt.alpn_string = q;
		} else if (strcmp(p, "fallback") == 0) {
			switch (atoi(q)) {
			case 0: opt.fallback = MBEDTLS_SSL_IS_NOT_FALLBACK; break;
			case 1: opt.fallback = MBEDTLS_SSL_IS_FALLBACK; break;
			default: goto usage;
			}
		} else if (strcmp(p, "extended_ms") == 0) {
			switch (atoi(q)) {
			case 0: opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_DISABLED; break;
			case 1: opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED; break;
			default: goto usage;
			}
		} else if (strcmp(p, "etm") == 0) {
			switch (atoi(q)) {
			case 0: opt.etm = MBEDTLS_SSL_ETM_DISABLED; break;
			case 1: opt.etm = MBEDTLS_SSL_ETM_ENABLED; break;
			default: goto usage;
			}
		} else if (strcmp(p, "min_version") == 0) {
			if (strcmp(q, "ssl3") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_0;
			} else if (strcmp(q, "tls1") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_1;
			} else if (strcmp(q, "tls1_1") == 0 ||
				   strcmp(q, "dtls1") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
			} else if (strcmp(q, "tls1_2") == 0 ||
				   strcmp(q, "dtls1_2") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
			} else {
				goto usage;
			}
		} else if (strcmp(p, "max_version") == 0) {
			if (strcmp(q, "ssl3") == 0) {
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_0;
			} else if (strcmp(q, "tls1") == 0) {
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_1;
			} else if (strcmp(q, "tls1_1") == 0 ||
				   strcmp(q, "dtls1") == 0) {
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
			} else if (strcmp(q, "tls1_2") == 0 ||
				   strcmp(q, "dtls1_2") == 0) {
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
			} else {
				goto usage;
			}
		} else if (strcmp(p, "arc4") == 0) {
			switch (atoi(q)) {
			case 0:     opt.arc4 = MBEDTLS_SSL_ARC4_DISABLED;   break;
			case 1:     opt.arc4 = MBEDTLS_SSL_ARC4_ENABLED;    break;
			default:    goto usage;
			}
		} else if (strcmp(p, "force_version") == 0) {
			if (strcmp(q, "ssl3") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_0;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_0;
			} else if (strcmp(q, "tls1") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_1;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_1;
			} else if (strcmp(q, "tls1_1") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
			} else if (strcmp(q, "tls1_2") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
			} else if (strcmp(q, "dtls1") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			} else if (strcmp(q, "dtls1_2") == 0) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			} else   {
				goto usage;
			}
		} else if (strcmp(p, "auth_mode") == 0) {
			if (strcmp(q, "none") == 0) {
				opt.auth_mode = MBEDTLS_SSL_VERIFY_NONE;
			} else if (strcmp(q, "optional") == 0) {
				opt.auth_mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
			} else if (strcmp(q, "required") == 0) {
				opt.auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
			} else {
				goto usage;
			}
		} else if (strcmp(p, "max_frag_len") == 0) {
			if (strcmp(q, "512") == 0) {
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_512;
			} else if (strcmp(q, "1024") == 0) {
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_1024;
			} else if (strcmp(q, "2048") == 0) {
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_2048;
			} else if (strcmp(q, "4096") == 0) {
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_4096;
			} else {
				goto usage;
			}
		} else if (strcmp(p, "trunc_hmac") == 0) {
			switch (atoi(q)) {
			case 0: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_DISABLED; break;
			case 1: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED; break;
			default: goto usage;
			}
		} else if (strcmp(p, "hs_timeout") == 0) {
			if ((p = strchr(q, '-')) == NULL) {
				goto usage;
			}
			*p++ = '\0';
			opt.hs_to_min = atoi(q);
			opt.hs_to_max = atoi(p);
			if (opt.hs_to_min == 0 || opt.hs_to_max < opt.hs_to_min) {
				goto usage;
			}
		} else if (strcmp(p, "recsplit") == 0) {
			opt.recsplit = atoi(q);
			if (opt.recsplit < 0 || opt.recsplit > 1) {
				goto usage;
			}
		} else if (strcmp(p, "dhmlen") == 0) {
			opt.dhmlen = atoi(q);
			if (opt.dhmlen < 0) {
				goto usage;
			}
		} else   {
			goto usage;
		}
	}

#if defined(MBEDTLS_DEBUG_C)
	mbedtls_debug_set_threshold(opt.debug_level);
#endif

	if (opt.force_ciphersuite[0] > 0) {
		const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
		ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(opt.force_ciphersuite[0]);

		if (opt.max_version != -1 &&
		    ciphersuite_info->min_minor_ver > opt.max_version) {
			mbedtls_printf("forced ciphersuite not allowed with this protocol version\n");
			ret = 2;
			goto usage;
		}
		if (opt.min_version != -1 &&
		    ciphersuite_info->max_minor_ver < opt.min_version) {
			mbedtls_printf("forced ciphersuite not allowed with this protocol version\n");
			ret = 2;
			goto usage;
		}

		/* If the server selects a version that's not supported by
		 * this suite, then there will be no common ciphersuite... */
		if (opt.max_version == -1 ||
		    opt.max_version > ciphersuite_info->max_minor_ver) {
			opt.max_version = ciphersuite_info->max_minor_ver;
		}
		if (opt.min_version < ciphersuite_info->min_minor_ver) {
			opt.min_version = ciphersuite_info->min_minor_ver;
			/* DTLS starts with TLS 1.1 */
			if (opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
			    opt.min_version < MBEDTLS_SSL_MINOR_VERSION_2) {
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
			}
		}

		/* Enable RC4 if needed and not explicitly disabled */
		if (ciphersuite_info->cipher == MBEDTLS_CIPHER_ARC4_128) {
			if (opt.arc4 == MBEDTLS_SSL_ARC4_DISABLED) {
				mbedtls_printf("forced RC4 ciphersuite with RC4 disabled\n");
				ret = 2;
				goto usage;
			}

			opt.arc4 = MBEDTLS_SSL_ARC4_ENABLED;
		}
	}

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
	/*
	 * Unhexify the pre-shared key if any is given
	 */
	if (strlen(opt.psk)) {
		unsigned char c;
		size_t j;

		if (strlen(opt.psk) % 2 != 0) {
			mbedtls_printf("pre-shared key not valid hex\n");
			goto exit;
		}

		psk_len = strlen(opt.psk) / 2;

		for (j = 0; j < strlen(opt.psk); j += 2) {
			c = opt.psk[j];
			if (c >= '0' && c <= '9') {
				c -= '0';
			} else if (c >= 'a' && c <= 'f') {
				c -= 'a' - 10;
			} else if (c >= 'A' && c <= 'F') {
				c -= 'A' - 10;
			} else {
				mbedtls_printf("pre-shared key not valid hex\n");
				goto exit;
			}
			psk[ j / 2 ] = c << 4;

			c = opt.psk[j + 1];
			if (c >= '0' && c <= '9') {
				c -= '0';
			} else if (c >= 'a' && c <= 'f') {
				c -= 'a' - 10;
			} else if (c >= 'A' && c <= 'F') {
				c -= 'A' - 10;
			} else {
				mbedtls_printf("pre-shared key not valid hex\n");
				goto exit;
			}
			psk[ j / 2 ] |= c;
		}
	}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */

#if defined(MBEDTLS_SSL_ALPN)
	if (opt.alpn_string != NULL) {
		p = (char *) opt.alpn_string;
		i = 0;

		/* Leave room for a final NULL in alpn_list */
		while (i < (int) sizeof alpn_list - 1 && *p != '\0') {
			alpn_list[i++] = p;

			/* Terminate the current string and move on to next one */
			while (*p != ',' && *p != '\0') {
				p++;
			}
			if (*p == ',') {
				*p++ = '\0';
			}
		}
	}
#endif /* MBEDTLS_SSL_ALPN */

	/*
	 * 0. Initialize the RNG and the session data
	 */
	mbedtls_printf("\n  . Seeding the random number generator...");
	fflush(stdout);

	mbedtls_entropy_init(&entropy);
	if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
					 (const unsigned char *) pers,
					 strlen(pers))) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ctr_drbg_seed returned -0x%x\n", -ret);
		goto exit;
	}

	mbedtls_printf(" ok\n");

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	/*
	 * 1.1. Load the trusted CA
	 */
	mbedtls_printf("  . Loading the CA root certificate ...");
	fflush(stdout);

#if defined(MBEDTLS_FS_IO)
	if (strlen(opt.ca_path)) {
		if (strcmp(opt.ca_path, "none") == 0) {
			ret = 0;
		} else {
			ret = mbedtls_x509_crt_parse_path(&cacert, opt.ca_path);
		}
	} else if (strlen(opt.ca_file)) {
		if (strcmp(opt.ca_file, "none") == 0) {
			ret = 0;
		} else {
			ret = mbedtls_x509_crt_parse_file(&cacert, opt.ca_file);
		}
	} else
#endif
#if defined(MBEDTLS_CERTS_C)
	for (i = 0; mbedtls_test_cas[i] != NULL; i++) {
		ret = mbedtls_x509_crt_parse(&cacert,
					     (const unsigned char *) mbedtls_test_cas[i],
					     mbedtls_test_cas_len[i]);
		if (ret != 0) {
			break;
		}
	}
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if (ret < 0) {
		mbedtls_printf(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
		goto exit;
	}

	mbedtls_printf(" ok (%d skipped)\n", ret);

	/*
	 * 1.2. Load own certificate and private key
	 *
	 * (can be skipped if client authentication is not required)
	 */
	mbedtls_printf("  . Loading the client cert. and key...");
	fflush(stdout);

#if defined(MBEDTLS_FS_IO)
	if (strlen(opt.crt_file)) {
		if (strcmp(opt.crt_file, "none") == 0) {
			ret = 0;
		} else {
			ret = mbedtls_x509_crt_parse_file(&clicert, opt.crt_file);
		}
	} else
#endif
#if defined(MBEDTLS_CERTS_C)
	ret = mbedtls_x509_crt_parse(&clicert, (const unsigned char *) mbedtls_test_cli_crt,
				     mbedtls_test_cli_crt_len);
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if (ret != 0) {
		mbedtls_printf(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
		goto exit;
	}

#if defined(MBEDTLS_FS_IO)
	if (strlen(opt.key_file)) {
		if (strcmp(opt.key_file, "none") == 0) {
			ret = 0;
		} else {
			ret = mbedtls_pk_parse_keyfile(&pkey, opt.key_file, "");
		}
	} else
#endif
#if defined(MBEDTLS_CERTS_C)
	ret = mbedtls_pk_parse_key(&pkey, (const unsigned char *) mbedtls_test_cli_key,
				   mbedtls_test_cli_key_len, NULL, 0);
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if (ret != 0) {
		mbedtls_printf(" failed\n  !  mbedtls_pk_parse_key returned -0x%x\n\n", -ret);
		goto exit;
	}

	mbedtls_printf(" ok\n");
#endif /* MBEDTLS_X509_CRT_PARSE_C */

	/*
	 * 2. Start the connection
	 */
	if (opt.server_addr == NULL) {
		opt.server_addr = opt.server_name;
	}

	mbedtls_printf("  . Connecting to %s/%s/%s...",
		       opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ? "tcp" : "udp",
		       opt.server_addr, opt.server_port);
	fflush(stdout);

	if ((ret = mbedtls_net_connect(&server_fd, opt.server_addr, opt.server_port,
				       opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
				       MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP)) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret);
		goto exit;
	}

	if (opt.nbio > 0) {
		ret = mbedtls_net_set_nonblock(&server_fd);
	} else {
		ret = mbedtls_net_set_block(&server_fd);
	}
	if (ret != 0) {
		mbedtls_printf(" failed\n  ! net_set_(non)block() returned -0x%x\n\n", -ret);
		goto exit;
	}

	mbedtls_printf(" ok\n");

	/*
	 * 3. Setup stuff
	 */
	mbedtls_printf("  . Setting up the SSL/TLS structure...");
	fflush(stdout);

	if ((ret = mbedtls_ssl_config_defaults(&conf,
					       MBEDTLS_SSL_IS_CLIENT,
					       opt.transport,
					       MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ssl_config_defaults returned -0x%x\n\n", -ret);
		goto exit;
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if (opt.debug_level > 0) {
		mbedtls_ssl_conf_verify(&conf, my_verify, NULL);
	}
#endif

	if (opt.auth_mode != DFL_AUTH_MODE) {
		mbedtls_ssl_conf_authmode(&conf, opt.auth_mode);
	}

#if defined(MBEDTLS_SSL_PROTO_DTLS)
	if (opt.hs_to_min != DFL_HS_TO_MIN || opt.hs_to_max != DFL_HS_TO_MAX) {
		mbedtls_ssl_conf_handshake_timeout(&conf, opt.hs_to_min, opt.hs_to_max);
	}
#endif /* MBEDTLS_SSL_PROTO_DTLS */

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
	if ((ret = mbedtls_ssl_conf_max_frag_len(&conf, opt.mfl_code)) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_max_frag_len returned %d\n\n", ret);
		goto exit;
	}
#endif

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
	if (opt.trunc_hmac != DFL_TRUNC_HMAC) {
		mbedtls_ssl_conf_truncated_hmac(&conf, opt.trunc_hmac);
	}
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
	if (opt.extended_ms != DFL_EXTENDED_MS) {
		mbedtls_ssl_conf_extended_master_secret(&conf, opt.extended_ms);
	}
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
	if (opt.etm != DFL_ETM) {
		mbedtls_ssl_conf_encrypt_then_mac(&conf, opt.etm);
	}
#endif

#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
	if (opt.recsplit != DFL_RECSPLIT) {
		mbedtls_ssl_conf_cbc_record_splitting(&conf, opt.recsplit
									? MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED
									: MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED);
	}
#endif

#if defined(MBEDTLS_DHM_C)
	if (opt.dhmlen != DFL_DHMLEN) {
		mbedtls_ssl_conf_dhm_min_bitlen(&conf, opt.dhmlen);
	}
#endif

#if defined(MBEDTLS_SSL_ALPN)
	if (opt.alpn_string != NULL) {
		if ((ret = mbedtls_ssl_conf_alpn_protocols(&conf, alpn_list)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_alpn_protocols returned %d\n\n", ret);
			goto exit;
		}
	}
#endif

	mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);
	mbedtls_ssl_conf_dbg(&conf, my_debug, stdout);

	mbedtls_ssl_conf_read_timeout(&conf, opt.read_timeout);

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
	mbedtls_ssl_conf_session_tickets(&conf, opt.tickets);
#endif

	if (opt.force_ciphersuite[0] != DFL_FORCE_CIPHER) {
		mbedtls_ssl_conf_ciphersuites(&conf, opt.force_ciphersuite);
	}

#if defined(MBEDTLS_ARC4_C)
	if (opt.arc4 != DFL_ARC4) {
		mbedtls_ssl_conf_arc4_support(&conf, opt.arc4);
	}
#endif

	if (opt.allow_legacy != DFL_ALLOW_LEGACY) {
		mbedtls_ssl_conf_legacy_renegotiation(&conf, opt.allow_legacy);
	}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
	mbedtls_ssl_conf_renegotiation(&conf, opt.renegotiation);
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if (strcmp(opt.ca_path, "none") != 0 &&
	    strcmp(opt.ca_file, "none") != 0) {
		mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
	}
	if (strcmp(opt.crt_file, "none") != 0 &&
	    strcmp(opt.key_file, "none") != 0) {
		if ((ret = mbedtls_ssl_conf_own_cert(&conf, &clicert, &pkey)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret);
			goto exit;
		}
	}
#endif

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
	if ((ret = mbedtls_ssl_conf_psk(&conf, psk, psk_len,
					(const unsigned char *) opt.psk_identity,
					strlen(opt.psk_identity))) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_psk returned %d\n\n", ret);
		goto exit;
	}
#endif

	if (opt.min_version != DFL_MIN_VERSION) {
		mbedtls_ssl_conf_min_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.min_version);
	}

	if (opt.max_version != DFL_MAX_VERSION) {
		mbedtls_ssl_conf_max_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.max_version);
	}

#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
	if (opt.fallback != DFL_FALLBACK) {
		mbedtls_ssl_conf_fallback(&conf, opt.fallback);
	}
#endif

	if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ssl_setup returned -0x%x\n\n", -ret);
		goto exit;
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if ((ret = mbedtls_ssl_set_hostname(&ssl, opt.server_name)) != 0) {
		mbedtls_printf(" failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
		goto exit;
	}
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
	if (opt.ecjpake_pw != DFL_ECJPAKE_PW) {
		if ((ret = mbedtls_ssl_set_hs_ecjpake_password(&ssl,
							       (const unsigned char *) opt.ecjpake_pw,
							       strlen(opt.ecjpake_pw))) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_set_hs_ecjpake_password returned %d\n\n", ret);
			goto exit;
		}
	}
#endif

	if (opt.nbio == 2) {
		mbedtls_ssl_set_bio(&ssl, &server_fd, my_send, my_recv, NULL);
	} else {
		mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv,
				    opt.nbio == 0 ? mbedtls_net_recv_timeout : NULL);
	}

#if defined(MBEDTLS_TIMING_C)
	mbedtls_ssl_set_timer_cb(&ssl, &timer, mbedtls_timing_set_delay,
				 mbedtls_timing_get_delay);
#endif

	mbedtls_printf(" ok\n");

	/*
	 * 4. Handshake
	 */
	mbedtls_printf("  . Performing the SSL/TLS handshake...");
	fflush(stdout);

	while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
		if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n", -ret);
			if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
				mbedtls_printf(
					"    Unable to verify the server's certificate. "
					"Either it is invalid,\n"
					"    or you didn't set ca_file or ca_path "
					"to an appropriate value.\n"
					"    Alternatively, you may want to use "
					"auth_mode=optional for testing purposes.\n");
			}
			mbedtls_printf("\n");
			goto exit;
		}
	}

	mbedtls_printf(" ok\n    [ Protocol is %s ]\n    [ Ciphersuite is %s ]\n",
		       mbedtls_ssl_get_version(&ssl), mbedtls_ssl_get_ciphersuite(&ssl));

	if ((ret = mbedtls_ssl_get_record_expansion(&ssl)) >= 0) {
		mbedtls_printf("    [ Record expansion is %d ]\n", ret);
	} else {
		mbedtls_printf("    [ Record expansion is unknown (compression) ]\n");
	}

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
	mbedtls_printf("    [ Maximum fragment length is %u ]\n",
		       (unsigned int) mbedtls_ssl_get_max_frag_len(&ssl));
#endif

#if defined(MBEDTLS_SSL_ALPN)
	if (opt.alpn_string != NULL) {
		const char *alp = mbedtls_ssl_get_alpn_protocol(&ssl);
		mbedtls_printf("    [ Application Layer Protocol is %s ]\n",
			       alp ? alp : "(none)");
	}
#endif

	if (opt.reconnect != 0) {
		mbedtls_printf("  . Saving session for reuse...");
		fflush(stdout);

		if ((ret = mbedtls_ssl_get_session(&ssl, &saved_session)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_get_session returned -0x%x\n\n", -ret);
			goto exit;
		}

		mbedtls_printf(" ok\n");
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	/*
	 * 5. Verify the server certificate
	 */
	mbedtls_printf("  . Verifying peer X.509 certificate...");

	if ((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0) {
		char vrfy_buf[512];

		mbedtls_printf(" failed\n");

		mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "  ! ", flags);

		mbedtls_printf("%s\n", vrfy_buf);
	} else   {
		mbedtls_printf(" ok\n");
	}

	if (mbedtls_ssl_get_peer_cert(&ssl) != NULL) {
		mbedtls_printf("  . Peer certificate information    ...\n");
		mbedtls_x509_crt_info((char *) buf, sizeof(buf) - 1, "      ",
				      mbedtls_ssl_get_peer_cert(&ssl));
		mbedtls_printf("%s\n", buf);
	}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_RENEGOTIATION)
	if (opt.renegotiate) {
		/*
		 * Perform renegotiation (this must be done when the server is waiting
		 * for input from our side).
		 */
		mbedtls_printf("  . Performing renegotiation...");
		fflush(stdout);
		while ((ret = mbedtls_ssl_renegotiate(&ssl)) != 0) {
			if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
			    ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
				mbedtls_printf(" failed\n  ! mbedtls_ssl_renegotiate returned %d\n\n", ret);
				goto exit;
			}
		}
		mbedtls_printf(" ok\n");
	}
#endif /* MBEDTLS_SSL_RENEGOTIATION */

	/*
	 * 6. Write the GET request
	 */
	retry_left = opt.max_resend;
send_request:
	mbedtls_printf("  > Write to server:");
	fflush(stdout);

	len = mbedtls_snprintf((char *) buf, sizeof(buf) - 1, GET_REQUEST,
			       opt.request_page);
	tail_len = (int) strlen(GET_REQUEST_END);

	/* Add padding to GET request to reach opt.request_size in length */
	if (opt.request_size != DFL_REQUEST_SIZE &&
	    len + tail_len < opt.request_size) {
		memset(buf + len, 'A', opt.request_size - len - tail_len);
		len += opt.request_size - len - tail_len;
	}

	strncpy((char *) buf + len, GET_REQUEST_END, sizeof(buf) - len - 1);
	len += tail_len;

	/* Truncate if request size is smaller than the "natural" size */
	if (opt.request_size != DFL_REQUEST_SIZE &&
	    len > opt.request_size) {
		len = opt.request_size;

		/* Still end with \r\n unless that's really not possible */
		if (len >= 2) {
			buf[len - 2] = '\r';
		}
		if (len >= 1) {
			buf[len - 1] = '\n';
		}
	}

	if (opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM) {
		for (written = 0, frags = 0; written < len; written += ret, frags++) {
			while ((ret = mbedtls_ssl_write(&ssl, buf + written, len - written))
			       <= 0) {
				if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
				    ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
					mbedtls_printf(" failed\n  ! mbedtls_ssl_write returned -0x%x\n\n", -ret);
					goto exit;
				}
			}
		}
	} else   { /* Not stream, so datagram */
		do{
			ret = mbedtls_ssl_write(&ssl, buf, len);
		}while (ret == MBEDTLS_ERR_SSL_WANT_READ ||
			ret == MBEDTLS_ERR_SSL_WANT_WRITE);

		if (ret < 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_write returned %d\n\n", ret);
			goto exit;
		}

		frags = 1;
		written = ret;
	}

	buf[written] = '\0';
	mbedtls_printf(" %d bytes written in %d fragments\n\n%s\n", written, frags, (char *) buf);

	/*
	 * 7. Read the HTTP response
	 */
	mbedtls_printf("  < Read from server:");
	fflush(stdout);

	/*
	 * TLS and DTLS need different reading styles (stream vs datagram)
	 */
	if (opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM) {
		do{
			len = sizeof(buf) - 1;
			memset(buf, 0, sizeof(buf));
			ret = mbedtls_ssl_read(&ssl, buf, len);

			if (ret == MBEDTLS_ERR_SSL_WANT_READ ||
			    ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
				continue;
			}

			if (ret <= 0) {
				switch (ret) {
				case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
					mbedtls_printf(" connection was closed gracefully\n");
					ret = 0;
					goto close_notify;

				case 0:
				case MBEDTLS_ERR_NET_CONN_RESET:
					mbedtls_printf(" connection was reset by peer\n");
					ret = 0;
					goto reconnect;

				default:
					mbedtls_printf(" mbedtls_ssl_read returned -0x%x\n", -ret);
					goto exit;
				}
			}

			len = ret;
			buf[len] = '\0';
			mbedtls_printf(" %d bytes read\n\n%s", len, (char *) buf);

			/* End of message should be detected according to the syntax of the
			 * application protocol (eg HTTP), just use a dummy test here. */
			if (ret > 0 && buf[len - 1] == '\n') {
				ret = 0;
				break;
			}
		}while (1);
	} else   { /* Not stream, so datagram */
		len = sizeof(buf) - 1;
		memset(buf, 0, sizeof(buf));

		do{
			ret = mbedtls_ssl_read(&ssl, buf, len);
		}while (ret == MBEDTLS_ERR_SSL_WANT_READ ||
			ret == MBEDTLS_ERR_SSL_WANT_WRITE);

		if (ret <= 0) {
			switch (ret) {
			case MBEDTLS_ERR_SSL_TIMEOUT:
				mbedtls_printf(" timeout\n");
				if (retry_left-- > 0) {
					goto send_request;
				}
				goto exit;

			case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
				mbedtls_printf(" connection was closed gracefully\n");
				ret = 0;
				goto close_notify;

			default:
				mbedtls_printf(" mbedtls_ssl_read returned -0x%x\n", -ret);
				goto exit;
			}
		}

		len = ret;
		buf[len] = '\0';
		mbedtls_printf(" %d bytes read\n\n%s", len, (char *) buf);
		ret = 0;
	}

	/*
	 * 7b. Simulate hard reset and reconnect from same port?
	 */
	if (opt.reconnect_hard != 0) {
		opt.reconnect_hard = 0;

		mbedtls_printf("  . Restarting connection from same port...");
		fflush(stdout);

		if ((ret = mbedtls_ssl_session_reset(&ssl)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n", -ret);
			goto exit;
		}

		while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
			if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
			    ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
				mbedtls_printf(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret);
				goto exit;
			}
		}

		mbedtls_printf(" ok\n");

		goto send_request;
	}

	/*
	 * 7c. Continue doing data exchanges?
	 */
	if (--opt.exchanges > 0) {
		goto send_request;
	}

	/*
	 * 8. Done, cleanly close the connection
	 */
close_notify:
	mbedtls_printf("  . Closing the connection...");
	fflush(stdout);

	/* No error checking, the connection might be closed already */
	do{
		ret = mbedtls_ssl_close_notify(&ssl);
	}while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
	ret = 0;

	mbedtls_printf(" done\n");

	/*
	 * 9. Reconnect?
	 */
reconnect:
	if (opt.reconnect != 0) {
		--opt.reconnect;

		mbedtls_net_free(&server_fd);

#if defined(MBEDTLS_TIMING_C)
		if (opt.reco_delay > 0) {
			mbedtls_net_usleep(1000000 * opt.reco_delay);
		}
#endif

		mbedtls_printf("  . Reconnecting with saved session...");

		if ((ret = mbedtls_ssl_session_reset(&ssl)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n", -ret);
			goto exit;
		}

		if ((ret = mbedtls_ssl_set_session(&ssl, &saved_session)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_session returned %d\n\n", ret);
			goto exit;
		}

		if ((ret = mbedtls_net_connect(&server_fd, opt.server_addr, opt.server_port,
					       opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
					       MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP)) != 0) {
			mbedtls_printf(" failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret);
			goto exit;
		}

		if (opt.nbio > 0) {
			ret = mbedtls_net_set_nonblock(&server_fd);
		} else {
			ret = mbedtls_net_set_block(&server_fd);
		}
		if (ret != 0) {
			mbedtls_printf(" failed\n  ! net_set_(non)block() returned -0x%x\n\n",
				       -ret);
			goto exit;
		}

		while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
			if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
			    ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
				mbedtls_printf(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret);
				goto exit;
			}
		}

		mbedtls_printf(" ok\n");

		goto send_request;
	}

	/*
	 * Cleanup and exit
	 */
exit:
#ifdef MBEDTLS_ERROR_C
	if (ret != 0) {
		char error_buf[100];
		mbedtls_strerror(ret, error_buf, 100);
		mbedtls_printf("Last error was: -0x%X - %s\n\n", -ret, error_buf);
	}
#endif

	mbedtls_net_free(&server_fd);

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	mbedtls_x509_crt_free(&clicert);
	mbedtls_x509_crt_free(&cacert);
	mbedtls_pk_free(&pkey);
#endif
	mbedtls_ssl_session_free(&saved_session);
	mbedtls_ssl_free(&ssl);
	mbedtls_ssl_config_free(&conf);
	mbedtls_ctr_drbg_free(&ctr_drbg);
	mbedtls_entropy_free(&entropy);

#if defined(_WIN32)
	mbedtls_printf("  + Press Enter to exit this program.\n");
	fflush(stdout); getchar();
#endif

	// Shell can not handle large exit numbers -> 1 for errors
	if (ret < 0) {
		ret = 1;
	}

	return(ret);
}
#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
                  MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C &&
                  MBEDTLS_CTR_DRBG_C MBEDTLS_TIMING_C */
